1. Field of the Disclosure
The invention generally relates to a nib assembly for a writing instrument and more specifically to a nib assembly having a ferrule including a double wall to prevent transfer of ink from an inner surface of a cap to a gripping surface of the ferrule.
2. Related Technology
As is well known, writing instruments include a writing nib that extends from a barrel or body. The writing nib is often protected from the environment by a cap when not in use. The cap can also prevent or minimize evaporation of the volatile compounds (most typically solvents) often found in inks from the writing nib. More volatile inks are often delivered by a porous or fibrous writing nib. Some inks may be delivered by a brush-type writing nib. Examples of such writing instruments include so called “paint brush markers” having a flexible layered writing nib that produces a brush-like stroke of ink.
Some writing instruments have included a movable inner cap to provide a secondary seal between the cap and the writing nib. The movable inner cap is slidable along a longitudinal cap axis and biased towards the cap opening by a spring. While such an arrangement provides an additional seal between the movable inner cap and the ferrule, this type of arrangement greatly increases the manufacturing complexity and costs.